The present invention relates to a bus driver, and more particularly to a bus driver for a high-speed data transmission.
In an information processing apparatus (e.g., a computer), data is transmitted between a plurality of logic blocks (i.e., large-scale-integrated circuit (LSI) chips) through a bus circuit, which comprises a bus, a bus driver and a bus receiver.
The bus driver sends the signal to the bus by controlling a voltage of the bus to a high level or to a low level. The bus receiver reproduces the signal by detecting the voltage of the bus.
High-speed data transmission requires a powerful bus driver that can feed a large current to the bus in a short period of time. The power of the bus driver can be improved, for example, by driving a bus line with a plurality of bus drivers.
The improvement of the bus driver's power results in an increased though-rate, which is an important factor of high-speed data transmission. However, as the through-rate is increased, an unacceptable deformation appears in the signals through the bus.
The main factor of this deformation is the reflection signal from the end of the bus. The reflection signal is an attenuating wave caused by the resistance and capacitance existing in the bus. The bus driver cannot send the next signal until the reflection signal attenuates enough so as not to disturb the next signal. The attenuation of the reflection signal takes a considerable period of time. Therefore, a high-power bus driver itself cannot improve the throughput sufficiently.